The preparation, isolation and purification of gentamycin is described in U.S. Pat. No. 3,091,572. Gentamycin, now known as gentamicin, was described in the patent as the principal antibiotic component and is referred to herein as the C-component or gentamicin C. In the patent, reference is made to co-produced antibiotics BA-5 (Fraction A) and BA-3 (Fraction B) which in admixture with each other exhibited a low order of antibacterial activity. These were separated from gentamicin C.
By the utilisation of a particular chromatographic system described later herein, we have found that the substances described in U.S. Pat. No. 3,091,572 as co-produced antibiotics BA-3 (Fraction A) and BA-3 (Fraction B) are not single entities unto themselves but together they represent a mixture of at least four components. Resolution of this mixture of the co-produced antibiotics into its components (hereinafter called gentamicin A, gentamicin B, gentamicin B.sub.1 and gentamicin X), has led to the discovery that each member of this group possesses surprising and unexpected applied-use characteristics.
Gentamicin A has been previously isolated in pure form, investigated chemically and biologically and found to have rather weak antibiotic activity. We have discovered the rather surprising applied-use characteristic of gentamicin A, namely, its utility as an antiprotozoal agent. Gentamicin B, gentamicin B.sub.1 and gentamicin X heretofore have never been isolated one from the other. We have discovered that these substances possess certain valuable properties as antibiotics, anthelmintic and antiprotozoal agents.